Deciphering Hydrodynamic and Drug-Resistant Behaviors of Metastatic EMT Breast Cancer Cells Moving in a Constricted Microcapillary.

Binita Nath,Amaresh Dalal,Anil P. Bidkar,Siddhartha S. Ghosh,Vikash Kumar,Gautam Biswas,Mohit Kumar Jolly

doi:10.3390/jcm8081194

Abstract

Epithelial to mesenchymal transition (EMT) induces cell migration, invasion, and drug resistance, and consequently, contributes to cancer metastasis and disease aggressiveness. This study attempted to address crucial biological parameters to correlate EMT and drug-treated cancer cells traversing through microcapillaries, reminiscent of metastatic conditions. MDA-MB-468 breast cancer cells induced to undergo EMT by treatment with 20 ng/mL of epidermal growth factor (EGF) were initially passed through several blockages and then through a constricted microchannel, mimicking the flow of invasive metastatic cells through constricted blood microcapillaries. EMT cells acquired enhanced migratory properties and retained 50% viability, even after migration through wells 10–15 μm in size and a constricted passage of 7 μm and 150 μm in length at a constant flow rate of 50 μL/h. The hydrodynamic properties revealed cellular deformation with a deformation index, average transit velocity, and entry time of 2.45, 12.3 mm/s, and 31,000 μs, respectively for a cell of average diameter 19 μm passing through one of the 7 μm constricted sections. Interestingly, cells collected at the channel outlet regained epithelial character, undergoing reverse transition (mesenchymal to epithelial transition, MET) in the absence of EGF. Remarkably, real-time polymerase chain reaction (PCR) analysis confirmed increases of 2- and 2.7-fold in the vimentin and fibronectin expression in EMT cells, respectively; however, their expression reduced to basal level in the MET cells. A scratch assay revealed the pronounced migratory nature of EMT cells compared with MET cells. Furthermore, the number of colonies formed from EMT cells and paclitaxel-treated EMT cells after passing through a constriction were found to be 95 ± 10 and 79 ± 4, respectively, confirming that the EMT cells were more drug resistant with a concomitant two-fold higher expression of the multi-drug resistance (MDR1) gene. Our results highlight the hydrodynamic and drug-evading properties of cells that have undergone an EMT, when passed through a constricted microcapillary that mimics their journey in blood circulation.

Highlights

Epithelial to mesenchymal transition (EMT) is a physiological phenotypic shift of epithelial to mesenchymal cells, where the breakdown of cell–cell and cell–extracellular matrix connections permits the migration of cells to distant locations [1]
EMT is involved in tumor progression with metastatic expansion and the generation of tumor cells with stem cell properties that play a major role in resistance to cancer treatment
This paper describes the flow of EMT cells in constricted microcapillaries while retaining their metastatic potential

Summary

Introduction

Epithelial to mesenchymal transition (EMT) is a physiological phenotypic shift of epithelial to mesenchymal cells, where the breakdown of cell–cell and cell–extracellular matrix connections permits the migration of cells to distant locations [1]. EMT is involved in tumor progression with metastatic expansion and the generation of tumor cells with stem cell properties that play a major role in resistance to cancer treatment. EMT and MET are not binary phenomena, and tumor cells can be in multiple hybrid states and express both epithelial and mesenchymal genes [5,6]. Such hybrid cells can move collectively as clusters and may be stem-like and metastatic compared with cells with a complete EMT phenotype [7,8]. The expression pattern of these genes can be tracked to study the behavior of the cells while transitioning from epithelial to mesenchymal or vice versa

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Results

Conclusion